Refactor test servers to make them less global.

test/transformer/cache_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS d.file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 
 const REPLACE_FROM_LIBRARY_TRANSFORMER = """
@@ skipping 153 matching lines @@
     process.stdout.expect("Goodbye!");
     process.shouldExit();
 
     d.dir(appPath, [
       d.dir(".pub/transformers", [
         d.file("manifest.txt", "0.1.2+3\nfoo"),
         d.matcherFile("transformers.snapshot", isNot(isEmpty))
       ])
     ]).validate();
 
-    servePackages((builder) {
+    globalPackageServer.add((builder) {
       builder.serve("foo", "2.0.0",
           deps: {'barback': 'any'},
           contents: [
         d.dir("lib", [
           d.file("transformer.dart", replaceTransformer("Hello", "New"))
         ])
       ]);
     });
 
     d.dir(appPath, [
@@ skipping 50 matching lines @@
         d.file("myapp.dart", "main() => print('Hello!');")
       ])
     ]).create();
 
     pubGet();
 
     var process = pubRun(args: ['myapp']);
     process.stdout.expect("Goodbye!");
     process.shouldExit();
 
-    servePackages((builder) {
+    globalPackageServer.add((builder) {
       builder.serve("bar", "2.0.0", contents: [
         d.dir("lib", [
           d.file("bar.dart", "final replacement = 'See ya';")
         ])
       ]);
     });
 
     d.dir(appPath, [
       d.pubspec({
         "name": "myapp",
@@ skipping 77 matching lines @@
   Future apply(Transform transform) {
     return transform.primaryInput.readAsString().then((contents) {
       transform.addOutput(new Asset.fromString(
           transform.primaryInput.id,
           contents.replaceAll("$input", "$output")));
     });
   }
 }
 """;
 }